Alright, let's solve this problem step by step. We have 3620 and 2039 and we're adding them together.

Step 1: We'll start by adding the digits 0 & 9 in column 1 and get 9.

Step 2: We'll start by adding the digits 2 & 3 in column 2 and get 5.

Step 3: We'll start by adding the digits 6 & 0 in column 3 and get 6.

Step 4: We'll start by adding the digits 3 & 2 in column 4 and get 5.

So, 3620 + 2039 = 5659.

